-Although differences of 0.2 eV in DFT calculations would generally be
-acknowledged to be insignificant when being compared to experimental
-results or data of other ab initio studies, these differences are
-considered to be reliable when comparing results, i.e. differences in
-energy, of a systematic study among each other. This is commonly done
-as can be seen in a great deal of literature, some of which is cited
-in the section of the present manuscript that investigates defect
-structures and formation energies. Very often differences less than
-0.2 eV are obtained and conclusions on the stability of a particular
-structure are derived.
+In literature, very often, differences less than 0.2 eV are obtained
+in DFT studies and respective conclusions are derived. For instance,
+differences in the energy of formation ranging from 0.05 - 0.12 eV are
+considered significant enough to conclude on the energetically most
+favorable intrinsic defect configurations in Si (PRB 68, 235205
+(2003); PRL 83, 2351 (1999)). This is due to the fact that existing
+errors are most probably of the systematic rather than the random
+type. The error in the estimate of the cohesive energy is canceled out
+since it is likewise wrong in the defect as in the bulk configuration,
+which are substracted in the expression of the defect formation
+energy. Even if the defect formation energy is overestimated due to a
+too small size of the supercell resulting in a non-zero interaction of
+the defect with its images, this is likewise true for other defects.
+Although the actual value might be wrong, observed differences in
+energy, thus, allow to draw conlcusions on the stability of defect
+configurations. This is also valid for diffusion barriers, which are
+given by differences in energy of different structures.
+In fact, differences of 0.2 eV in DFT calculations are considered
+insignificant when being compared to experimental results or data of
+other ab initio studies. However, the observed differences in energy
+within our systematic DFT study are considered reliable.